Recently, with an increase in the electricity demand and the consciousness of the global environment, there has been a rising momentum in saving power consumption in households and offices. With such growing sense of saving energy, such efforts is made that electric devices are frequently turned off and a setting temperature of an air conditioner is readjusted.
Various methods of measuring power consumption are proposed to grasp how much energy is actually saved with these efforts.
However, it is difficult in any of these methods to accurately measure a power consumption of an individual electrical device.
For example, a method is proposed in which a terminal to measure power consumption is provided in a home socket so as to measure the current power consumption of an electrical device connected to the socket. However, in this method, in the case where a power strip is connected to one wall power and a plurality of electrical devices are connected to the power strip, there is a problem that only the total amount of the power consumptions of the electrical devices can be measured, and the power consumption of each electrical device cannot be individually measured.
Also, there is a method in which a current sensor for measuring power consumption is provided to a power wire before being branched by a home distribution board. However, in this method, it is impossible to see how much power is consumed by each power wire after being branched by the distribution board.
Technologies relating to the background arts are disclosed in JPA 9-84146, JPA 10-97879, JPA 11-108971, and JPA 11-313441.